Table 3.

Average cross twin- cross trait tetrachoric correlations between insomnia, depression, and overanxious disorder in MZ and DZ twins

	MZ Twins			DZ Twins
	Insomnia	Depression	Overanxious Disorder	Insomnia	Depression	Overanxious Disorder
Insomnia	0.18*	0.10*	0.09*	0.05	0.10*	0.08
Depression		0.12*	0.12*		0.02	0.10*
Overanxious Disorder			0.25*			0.12*

P < 0.05